Once we used failjure, now it’s gone and we decided to use ex-info

Really promising alternative to me is missionary. With this approach we can finally make every components “pure”

My answer is the same regardless of Polylith: • for unexpected errors that local code cannot handle, throw an exception • for "expected" errors / failures that can be handled in local code, return some sort of error code or pair/hash map with either a successful result or details of the failure

You're on the JVM: lots of code you might call can throw exceptions; they are idiomatic on the JVM.

we use ex-info with a data that conforms to https://github.com/cognitect-labs/anomalies

if you’re writing higher performance code, and/or have a very large project , i also like https://github.com/redplanetlabs/defexception

We don’t support that today, but we could e.g. activate it by passing in something like :with-warnings to the info command. You can create an issue if you want.

You can do it with poly check via the API in 0.2.19. We do it at work in our build.clj file

As soon as I get to my desk, I'll share the code

This is what we have in our build.clj file:

(defn poly-check
  "Run the Polylith check command."
  [opts]
  (let [{:keys [ok? error-messages]} (poly/check)]
    (when-not ok?
      (doseq [{:keys [code colorized-message type]} error-messages]
        (println colorized-message ":" type code))
      (throw (ex-info "Polylith Check Failed!" {}))))
  opts)

We :require [polylith.clj.core.api.interface :as poly] in the build ns.

Thanks! I’ll copy and paste that code right away

poly/check doesn't catch warnings so I ended up like this.

- name: Check poly info
  run: |
    output=$(clojure -M:poly info color-mode:none)
    if echo "$output" | grep -q "Warning"; then
      warnings=$(echo "$output" | sed -n '/Warning/,$p')
      while IFS= read -r line; do
        echo "::warning::$line"
      done <<< "$warnings"
      exit 1
    fi

An option would be to make this configurable.

I'm a bit surprised that poly/check doesn't return warnings in that data structure -- guess I hadn't noticed (and failing on errors has been sufficient so far for us)?

Do you mean it doesn’t populate :messages or that it doesn’t return a code (e.g. 1)?

It returns a hash map with :ok? and :error-messages etc.

See the poly-check function I posted above, from our build.clj file at work.

Okay, then I think we understand each other! This could of course be configurable with something like treat-warning-as-error and then if we have a warning when running the test command, it could e.g. return with 1.

I don't think we do understand each other. In the API does the check function return warnings or just errors? Is :ok? still truthy in the presence of warnings? I'm not asking about anything else except that API function.

In the API does the check function return warnings or just errors? => just errors Is :ok? still truthy in the presence of warnings? => yes -- The validator that poly/check depends on only provides an interface for errors I guess. https://github.com/polyfy/polylith/blob/338b36f724c899e4fe994eb9d3dae9a37f04bd46/components/validator/src/polylith/clj/core/validator/core.clj

Okay, get it now. We only return errors right now. One solution could be to also include the warnings. The :ok? flag could work as today and be set if there are any errors.

That would be nice. So callers could check whether any warnings came back when :ok? is truthy. I'd like that.

Yes, that's my idea. We could add :has-warnings? or similar too.